Drawing inspiration from the morally ambiguous character of William Munny from Clint Eastwood's 1992 film Unforgiven, Silicon Knights conceived Kain as a nobleman murdered and revived as a vampire to take revenge on his assassins.

He has been favorably received by critics and fans, with praise centering around his memorable personality, nuanced characterization and moral greyness; his transition from protagonist in Blood Omen to antagonist in Legacy of Kain: Soul Reaver was positively singled out.

He and writer Ken McCulloch considered Simon Templeman's voiceover for the character superlative, despite initial apprehensions that the actors they had hired might not be able to convey the game's complicated dialogue.

In this game, which built upon the Blood Omen ending in which he damns the world, Kain adopted the role of antagonist, with new character Raziel serving as the lead.

No longer acting as a pure villain, Kain was intended to function as a "steadfast character", coming to the story from a position of knowledge in contrast to Raziel's relative ignorance.

Hennig expressed that, by Soul Reaver 2, her personal perception of Kain's character had changed over the years, and that she now considered him a somewhat more attractive and interesting individual than Raziel due to his complexity.

[9] The development staff chose to focus on his rise to power as a younger vampire, combining aspects of his Blood Omen and Soul Reaver incarnations.

[10][11] He was marketed as a more powerful and ruthless character than traditional video game heroes, with lead designer Mike Ellis inviting comparison to Final Fantasy VI's Kefka Palazzo and Revolver Ocelot of the Metal Gear series.

Design issues, raised by the wealth of abilities and equipment he accumulated in Blood Omen, prompted the team to add to his backstory and convincingly deprive him of these powers.

[9] Recognizing that he is "the most important character in the series",[14] designer Kyle Mannerberg named several parallels and influences concerning his development up to that point, citing Neo and John Murdoch (the protagonists of The Matrix and Dark City respectively), the archetypal Fisher King of Arthurian legend, the story of Oedipus, and Gnostic myth as inspirations[14] (with both latter sources being reaffirmed as strong influences by Hennig in a later interview[15]).

[14] Kain's appearance undergoes "pretty dramatic changes" throughout the games as he ages,[14] but core personality attributes cited by Defiance's developers include his intelligence and cynicism,[9] arrogance and regality,[9][16] and his defiant nature.

[15] In the series' fictional universe, he is described as the guardian of balance, a being responsible for preserving the health and integrity of Nosgoth (the games' setting), but left incapable of realizing this duty due to spiritual corruption that he inherited at birth.

[14] The character's transformation into a vampire, and the visceral nature this trait lends the series, was derived from William Shakespeare's classical models: "for the drunken commoners in the front rows he would insert dirty jokes to keep them entertained but for the aristocracy in the balconies he would write very cerebral metaphors".

In Blood Omen and Defiance, his battle cry and catchphrase is Vae victis, a Latin phrase attributed to Brennus meaning "woe to the conquered".

[38] Having viewed the timestream, he learned that history is predestined,[39] and seeks to change his fate by triggering more temporal paradoxes,[40][41] an objective which demanded Raziel's temporary destruction.

[45] Blood Omen 2 pursues a younger Kain during his early conquests of Nosgoth,[9] in the altered timeline triggered by the changes to Raziel's destiny at the end of Soul Reaver 2.

[58] Beyond the games, he also appeared in Top Cow's promotional comics for Soul Reaver and Defiance,[6][59] and was included alongside Raziel as a playable character in downloadable content for 2010's Lara Croft and the Guardian of Light.

[74][75] Some reviewers were less enthusiastic about aspects of the character, with IGN's Perry commenting that his Soul Reaver 2 dialogue was haughty and "overwritten",[76] and Ivan Sulic considering his Blood Omen 2 incarnation "nothing more than an arrogant jerk with little to latch on to and care about" while expressing preference for Raziel.

[77] Also relating to Blood Omen 2, IGN's Aaron Boulding regarded his pompous nature as his "one personality trait", and considered it comedic,[78] while Matt Casamassina felt Kain was "cool", but decried his visual design as "flamboyant to the point of being comical".

[79] Alex Lucard of DieHard GameFan described Kain as an interesting character and one of gaming's most memorable vampires, discussing how his personality shifted between a portrayal as a "petty jealous monster" and a "wise but arrogant ruler."